Curable resin compositions comprising thermosetting resins and poly(arylene ether) resins are known. However, it has been difficult to prepare thermosetting compositions comprising substantial amounts of higher molecular weight poly(arylene ether)s, for example, those having intrinsic viscosities of about 0.30 dL/g or greater (as measured at 25° C. in chloroform). As described, for example, in U.S. Pat. No. 4,912,172 to Hallgren et al., high temperatures are typically required to dissolve the poly(arylene ether)s in the thermosetting resin. High temperature, latent catalysts such as aluminum tris(acetylacetonate) can then be dissolved into the solution to initiate curing. However, the high temperatures required to prevent the poly(arylene ether) from precipitating out of solution are incompatible with the use of many cure agents, particularly amine cure agents, which would undergo a rapid and uncontrolled reaction at such elevated temperatures.
U.S. Pat. No. 4,623,558 to Lin describes a plastisol dispersion composition comprising (1) poly(phenylene oxide) in powder form, which is insoluble in the reactive plasticizer at room temperature and plasticizable at a temperature at or above the fluxing temperature; (2) a liquid reactive plasticizer member of the group consisting of (a) at least one epoxide resin having an average of more than one epoxide group in the molecule, (b) at least one liquid monomer, oligomer or prepolymer containing at least one ethylenically unsaturated group and (c) a mixture of (a) and (b); said liquid reactive plasticizer being capable of solvating the poly(phenylene oxide) at the fluxing temperature and being present in an amount ranging from 5 to 2,000 parts per 100 parts by weight of (1); and (3) 0.01 to 10% by weight of (2) of a latent curing agent, such as a thermal initiator or photoinitiator, for plasticizers present in the composition. The latent curing agents are not reactive with the thermoset resins at lower temperatures.
There remains a need for curable poly(arylene ether)-containing resin compositions that allow the poly(arylene ether) to remain in a workable state in the thermosetting resin at a temperature suitable for addition of a low-temperature cure agent. There also remains a need for curable poly(arylene ether)-containing resin compositions that form homogeneous solutions at lower temperature for intimate mixing of the poly(arylene ether) into the resin matrix.